sergeant



(No Model.) I 2 Sheets-Sheet 1. G. H. SERGEANT.

DOUBLE SCOTCH YOKE ENGINE.

144444139. Patented Jan.6,1891.

Fo'y. 1. 5

(No Model.)

0. H. SERGEANT.

2 Sheets-Sheet 2.

DOUBLE SCOTCH YOKE ENGINE.

Patented Jan. 6, 1891.

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UN TE v, STATES PAT T O F CE.

CHARLES H. SERGEANT, OF NE\V YORK, N. Y.

DOUBLE SCOTCH-YOKE ENGINE.

SPECIFICATION forming part of Letters Patent No. 444,139, dated January 6, 1891.

Application filed July 17, 1890.

To all whom it may concern:

Be it known that I, CHARLES H. SERGEANT, of the city and county of New York, in the State of New York, have invented a new and useful Improvement in Double Scotch-Yoke Engines, of which the following is a specification.

My invention relates to an improvement in engines of the double Scotch-yoke type with a view of diminishing the-size of the engine and the number of parts which enter into its construction without diminishing the power of the engine, and so rendering it particularly well adapted to use in connection with coalangers and other drills employed in mining and quarrying.

With these ends in View myinvention consists in certain features of construction and combinations and arrangements of parts, as will be hereinafter described, and pointed out in the claims.

A practical embodiment of my invention is represented in the accompanying drawings, in which- Figure 1 is a top plan View of the engine, showing one of the cylinders in horizontal section. Fig. 2 is a vertical section taken longitudinally through 'one of the cylinders as, for example, on the'line m a: of Fig. 1; and Fig. 3 is a vertical section centrally through the engine lengthwise of the main shaft, or at right angles to the section shown in Fig. 2.

A single steam-chest A is provided with a suitable bore for the reception of a pair of rocking valves a, which control the flow of steam to the pairs of double cylinders. The heads B of the steam-chest A project upwardly and form bearings Z) for the main shaft 0.

To the opposite sides of the steam-chest A a pair of double cylinders D, and D, preferably formed in a single piece, are secured by means of a single through -bolt E. The double cylinders D D have a tongue-andgroove connection with the sides of the steamchest, as shown at e, Fig. 2, by means of which the parts are held against any possibility of displacement when the nut on the throughbolt E is drawn up snugly. The said double cylinders D D have also a similar connection or lap over the chest-heads B to prevent Serial No. 359,068. (No' model.)

them from displacement when the said cylinders are locked in their position in assembled adjustment.

The main shaft 0 is located centrally between the pairs of double cylinders D D, and is provided at points in line with the axes of the cylinders D and the axes of the cylinders D with cranks c. A pair of pistons F are rigidly yoked together and adapted to reciprocate within the cylinders D, and a similar pair of pistons F are yoked rigidly together and adapted to reciprocate within the cylinders D. The yoke of each pair of pistons is provided with a sliding bearing f, which embraces the wrist-pin of the crank c of the main shaft. The cranks are set at right angles to each other to overcome dead-centers, as is usual.

The valve-operatin g rods 0 a are provided with cranks a and a, respectively, by means of which the valves are suitably rocked from eccentrics c and c fixed on the main shaft upon opposite sides of the engine.

The ports for the admission of steam to the opposite ends of the cylinders are represented by G and the exhaust-ports by g. As shown in Fig. 3, the exhaust-ports g are so located with respect to the cranks upon the main shaft where the sets of pistons are secured thereto that the exhaust of steam and oil will be thrown directly upon the crank-bearings, keeping them at all times well lubricated.

It will be observed that by seating both valves in the same bore within the chest and by interlocking the heads of the steam-chest with the double-cylinder castings, and at the same time fitting the steam-chest heads as bearings from the main shaft, I am able to secure a very compact arrangement of the parts without in any degree diminishing the strength and utility of the structure, while the arrangement is such as to utilize in a highly-advantageous manner the oil carried with the exhaust from the cylinders.

The double cylinder castings are here shown as provided with outwardly-projecting bosses H, provided with screw-threaded sockets h. The purpose of these bosses and their threaded sockets is to form a convenient means for the securing of a power-auger or its equivalent to the engine forminin g purposes.

An auger adapted to be so united to the engine to form a complete portable miningmachine is shown and described in an application executed and tiled by me of even date herewith.

\Vhat I claim as my invention is l. The combination, with two pairs of cylinders and a steam-chest common thereto and provided with a single bore to form valveseats, of a pair of valves, one for each pair of cylinders, seated in alig'mnent within said bore, and means for operating the valves, substantially as set forth.

The combination, with the steam-chest and cylinders havingan interlocking engagement therewith, of a single bolt for holding the cylinders and chest in assembled adjustment, substantially as set Forth.

1:3.- The combination, with the eylindc rs, the pistons, and the main shaft yoked to the pistons, of the steam-chest provided with laterally-extended heads which form bearings for the main shaft, substantially as set forth.

U1 I'ARLES II. SERG EAN'I. \Vitnesses:

D. II. HAYWOOD, L. N. LEGENDRE. 

